Suppression of classical stochasticity by quantum mechanical effects in the dynamics of periodically perturbed surface state electrons

We present the classical and the quantum mechanical descriptions of surface-state-electrons which are perturbed by a periodic force F(t)=eepsilonΣsub(n) delta(t- T). The numerical results are supported by analytical estimates which indicate that the stochastic behaviour which characterizes the classical treatment, and which is manifested by the energy diffusion and ionization rates is suppressed in the quantum treatment. (author)